NWS: ‘Tropical moisture surges’ prompt flood watch

Here we go again with more heavy rain and the timing couldn’t be worse.

This time it’s caused by Tropical Storm Michael.

Average rainfall amounts between one to 1.5 inches are expected, with locally higher amounts of 2 to 4 inches possible.

Any heavy rainfall that occurs within a 1 to 3 hour time frame may result in flash flooding. The heaviest rainfall is expected in and around New York City, and also across portions of Long Island and ... southern Connecticut.

The best chance of rain is between noon and 3 a.m., according to the National Weather Service’s hourly forecast.

The highest probability of thunderstorms and heaviest rain is from 3 and 6 p.m. - bad timing for PM commute.

In the last three weeks, there have been two times when heavy rain flooded local streets and major highways like the Merritt Parkway and I-95 during the afternoon drive home. On Sept. 26, up to 8 inches fell across southwest Connecticut. And on Oct. 3, nearly 4 inches of rain fell in a short period of time

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Because of this wet weather the NWS has posted a Flash Flood Watch for all of Connecticut and the New York City metro area.

There is also a Coastal Flood Advisory for the Fairfield and New Haven counties shoreline. High tide is expected to be about a foot above normal. High tide is around 1:30 p.m. Thursday and 2 a.m. Friday. For specific times, click here.

“As tropical moisture surges northward from Virginia and North Carolina, showers and a few thunderstorms should develop by afternoon,” it says.

“The rain may become heavy at times and could lead to some flooding concerns, and so a flash flood watch remains in effect. A few thunderstorms could also produce gusty winds late this afternoon, mainly in and around the greater New York City metropolitan area, where high temperatures will be closer to 80 and where more instability may develop than in areas farther north and east.

“The rain will continue into tonight, especially along coastal Connecticut, as a cold front moves into the area, and as additional tropical moisture interacts with the front.

“As the front moves out to sea and as a strong low pressure system,the remnant of Michael, passes southeast of Long Island on Friday, northwest winds will increase, especially along the coast, wherea few gusts of 35 to 40 mph are possible. Noticeably cooler and drier air will also move in, with high temperatures only in the 60s. Even cooler air will move in for the weekend as high pressure moves across.”

The forecast

Today: Showers and possibly a thunderstorm, mainly before 3 p.m., then showers and thunderstorms after 3pm. Some of the storms could produce gusty winds and heavy rain. High near 77. South wind 7 to 11 mph. Chance of precipitation is 100 percent. New rainfall amounts between three quarters and one inch possible.

Tonight: Showers and thunderstorms before 7 p.m., then showers and possibly a thunderstorm, mainly after 7 p.m. Some of the storms could produce heavy rainfall. Low around 58. Southwest wind 5 to 8 mph becoming northwest after midnight. Chance of precipitation is 90 percent. New rainfall amounts between three quarters and one inch possible.

Friday: Scattered showers before 8am. Cloudy through mid morning, then clearing, with a steady temperature around 62. Breezy, with a north wind 18 to 22 mph, with gusts as high as 33 mph. Chance of precipitation is 30 percent.

Friday Night: A 20 percent chance of showers after midnight. Partly cloudy, with a low around 47. Northwest wind 8 to 11 mph.

Saturday: A 30 percent chance of showers, mainly before 3pm. Partly sunny, with a high near 56. West wind 6 to 10 mph.